1st all grain, can someone check my math? - Home Brew Forums

 Home Brew Forums > 1st all grain, can someone check my math?

06-18-2011, 06:27 PM   #1
dfess1
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Mar 2011
Flourtown, PA
Posts: 1,411
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Hi,

I'm about to do our first AG tomorrow, and would like some clarification. My recipe has 24lbs of grain (pale ale, 10 gallon batch).

My math says (at a rate of 1.25 qts/lb) that I need 7.5 gallons of strike water at 162 degrees, then maintain 154 degrees.
I need 12 gallons of sparge water at 168 degrees. Is this correct?

I have purchased Beersmith, and quite frankly am having a hard time setting it up.

Thanks for any help.

06-18-2011, 06:44 PM   #2
wilserbrewer
BIAB Expert Tailor

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May 2007
Jersey Shore, New Jersey
Posts: 9,803
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Just spitballing here...but striking at 162 sounds low to hit a mash of 154. IME I would strike closer to 168 to land at 154. Much easier to strike high and temper down w/ either cool water or a few ice cubes.

As far as gallons of sparge water, i always find it simpler to measure the amount of wort needed on the final sparge, and sparge w/ that amount to reach your intended pre boil volume. Example: It matters none what the calculator says if you need 3.5 gallons more wort...then sparge 3.5 gallons

edit...here is a handy very simple brewing calc...http://www.rackers.org/calcs.shtml

fwiw it shows a strike of 171 for a mash of 154.

06-18-2011, 06:47 PM   #3
Ranger9913
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Oct 2009
Nashville
Posts: 299
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24lbs x 1.25 = 30qts/4 = 7.5 gallons so yes that is correct

The 1/2 gallon per pound of grain for sparge is not always accurate to me. You'll have to find what works well for your system. Start with a 12 gallons sparge and if you end up with 12 gallons total collection in the BK from your mash and sparge then you can adjust down. Or you can collect all the runnings and lengthen your boil time. I would recommend doing a double sparge. Do a 6 gallon sparge first, stir, rest for 25mins, drain. Do a second sparge amount based on how much of the initial 6 gallons you were able to collect and repeat.

In regards to the mash, 162 is assuming your mash tun is pre heated to at least 154 before you add water and grains. A cold or room temp mash tun will make you miss your mark for sure.

Your sparge water is going to be higher than 168, you want the mash tun to be 168 and you will have to raise the grain bed from 154 to 168.

06-18-2011, 09:06 PM   #4
PT Ray
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Aug 2005
Posts: 1,373
Liked 7 Times on 7 Posts

162 degree strike water sounds right if you preheat the mash tun and don't have to account for its thermal mass. I've seen brewers over heat the water, pour it in the mash tun and wait for it to drop to the strike temp. For me, 168 degree strike water with a 1.25qt water ratio will get me around a 154 degree mash in without preheating the mash tun.

The way a figure sparge water is a modified 2qt:1lb rule. I use a total of 3qts:1lb for mash and sparge. So if I'm using 1.25qt for mashing, sparge will be 1.75qt:1lb. This rarely gives me enough pre-boil volume and have to add some water to the kettle. But I feel more comfortable that I'm not over sparging.

06-23-2011, 06:24 AM   #5
millaj92

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Nov 2010
Plano, Texas
Posts: 142
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I start out planning to use 1 half gallon of sparge water per pound of grain. I fly sparge until the gravity of the run-off is 1.010. I rarely use all the sparge water and I have yet to drain all the liquid out of the lauter tun.
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